MULTI-MALE MATING BY PAIRED AND UNPAIRED FEMALE PRAIRIE VOLES (MICROTUS OCHROGASTER)

Abstract

AbstractPromiscuous mating is common in female rodents; however what role the female plays in this choice of mates is not clear. Also, whether MMM occurs in the reportedly socially monogamous prairie vole, Microtus ochrogaster, and what role mate-guarding plays in deterring MMM is not known. We conducted two experiments to determine if female prairie voles that were not mate-guarded would copulate with multiple males during a given oestrous period. In experiment 1 using females that were unpaired, we allowed females to choose among three males that were tethered and unable to interact with one another, thus eliminating male-male competition and mate guarding. MMM occurred in 55% of 47 trials. Females mated most often with males with whom they spent the most time, thus social preference was a good predictor of sexual preference. The tendency to mate with multiple males increased over time, thus the length of time a male mate guards can affect paternity. In experiment 2 with females that had been paired with a male and were in post-partum oestrus, 5 of 12 (42%) females mated with more than one male and 3 of 12 (25%) females deserted their paired mate and paired with a new novel male. Thus multi-male mating was similar for paired and unpaired females. Our results suggest that female prairie voles that are not mate-guarded will mate with multiple partners.